Abstract 1580: LCN2 is a therapeutic target against inflammatory breast cancer
Authors: Marienid Flores-Colon, Pablo E. Vivas-Mejia
Journal: Cancer Research (2023)

Abstract Breast cancer (BC) is the most common cancer type accounting for 12% of annual cancer cases worldwide. In the United States, 30% of the newly diagnosed cancer cases in woman are BC. Inflammatory breast cancer (IBC) is a rare and aggressive subtype of BC that accounts for 1 to 5% of all types of BC. Due to its inflammatory characteristics and the absence of a palpable mass, IBC is usually confounded with a mastitis. Once properly diagnosed, IBC has already metastasized. A high portion of IBC tumors overexpress human epidermal growth factor receptor 2 (HER2). These IBC patients (HER2+) are treated with Trastuzumab, a monoclonal antibody. However, many IBCs become resistant to this therapy. Thus, there is not an optimal treatment against this horrendous disease. One potential target against IBC is Lipocalin-2 (LCN2), a secreted protein involved in iron homeostasis, immune responses, transport of siderophores, and epithelial cell differentiation. In many aggressive tumors, high levels of LCN2 have been associated with increased cancer cell motility, proliferation, angiogenesis, invasion, and metastasis. Our research team published that LCN2 is aberrantly abundant in IBCs compared with non-IBC patients and cell lines and showed that small interference RNAs (siRNAs) targeting LCN2 effectively reduced the cell proliferation and invasion ability of IBC cells. Therefore, to understand the mechanisms involved after LCN2 knockdown, we did a RNA-sequencing using IBC3 cells transfected with LCN2-siRNA or with a negative control siRNA, where we identified 138 dysregulated genes. Genes as SOX18, which correlates to distant metastasis and poor clinical prognosis in cancer, and as LRP4, which correlates to proliferating clinical features by activating the PI3K/AKT pathway were identified. We used the Ingenuity Pathway Analysis software to identify the pathways regulated after LCN2 knockdown and found 25 canonical pathways altered. These results will be further validated by qPCR and Western Blot analysis. Also, after the identification of LCN2 as a plausible target for therapy against IBC, we worked on the preparation of a Herceptin-conjugated liposome loaded with siRNA against LCN2, to improve internalization in HER2+ IBC cells. We developed a three step reaction to obtain trastuzumab DSPE-PEG(2000) maleimide conjugates used to prepare the liposomal formulation. Trastuzumab conjugated liposomes were prepared and characterized using dynamic light scattering to measure their size distribution. Our formulation displayed sizes of 18.3 and 73.7 nm which could correspond to free DSPE-PEG(2000) trastuzumab and the trastuzumab-liposome, respectively. There is ongoing work to determine the optimal timepoint for internalization of liposomes into IBC cell lines and further treatment with liposomes charged with siRNA LCN2 to treat cell lines and determine the biological effect with the aim of developing a targeted treatment for inflammatory breast cancer. Citation Format: Marienid Flores-Colon, Pablo E. Vivas-Mejia. LCN2 is a therapeutic target against inflammatory breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1580.